Transducers transform one form of energy into another and can be characterized, for purposes herein, by a plurality of spaced, parallel transducer rods made of a piezoelectric material embedded in a rigid resin between a pair spaced, electrically conducting layers or plates disposed transversely to the rods. The rods can be considered to be disposed in the vertical Z direction and the conducting plates can be considered to be disposed in the transverse X,Y plane. In order to improve the sensitivity of the transducers, an air cylinder or a layer of a soft resin is provided around the transducer rods. Provision of air or soft resin around the rods attenuates lateral acoustic pressure fluctuations and results in an improved hydrostatic performance of the transducers.
One problem encountered in transducers is the inefficient transfer of a force between the cover plates and the transducer rods. In prior art transducers, when a force is imparted to a cover plate, only a fraction of that force is transmitted by the cover plate to the transducer rods and the rest of that force is transmitted by the cover plate to the matrix surrounding the rods. The matrix includes the rigid resin and the cylinder of air or soft resin around the rods. Most of the force transferred to the matrix is lost since the matrix is an inactive part of the transducer. The loss of the force fraction transmitted to the matrix means that the rods, which are the only active element in the transducer, do not receive and do not convert the full force imparted to the cover plate with the result that performance of the transducer is reduced.
The loss of force to the matrix is exacerbated in transducers that have a soft resin around the transducer rods. Since the soft resin is resilient and compressible, it is quite difficult to grind the soft resin to the level of the rods or to that of the rigid matrix and the result is bulging of the soft resin above the level of the rods or the rigid matrix. Consequently, only a small fraction of the applied force is transfessed to the active rods.